In recent years, in the medical field, a labor-saving test operation has been promoted by introducing various automation devices. In tests in a hospital, test specimens of hospital inpatients and outpatients are collected in each department in the hospital, and are collectively processed in a test room. A test item for each specimen is transferred from a doctor to the test room by using an online information processing system, and a result of the test is reversely reported online from the test room to the doctor. Most of test items for blood and urine require pre-analysis processing such as centrifugal processing, decap processing, and dispensing processing as the pre-analysis processing of the test processing, and a rate occupied in the entire test operation time by the operation for them is large.
The centrifugal processing of the pre-analysis processing is a processing for extracting serum components by performing centrifugation to the blood collected from a patient so as to obtain a test sample. Generally, an automatic centrifuge used in a specimen-test automation system has a plurality of bucket groups held by a rotating rotor so as to be swung. Each of the bucket groups is configured of a plurality of pair of buckets, and each of the pair of buckets is configured of buckets positioned rotation-symmetrically to each other across a rotation axis of the rotor. Into each of the buckets, a plurality of (for example, about 5 to 10) specimens are inserted while they are set on an adaptor and are held so as to stand up. Conventionally, the specimens have been inserted into the respective buckets by a human hand. However, an aim of a specimen-test automation system in which the pre-analysis processing is automated is to automate these operations.
The centrifugal operation is performed by rotating the rotor at high speed. Therefore, if weights of the buckets arranged at the pair of buckets are significantly different from each other, the rotation abnormality of the rotor is caused, and the centrifugal operation cannot be normally performed. Therefore, it is required to execute weight adjustment at a prior stage to installation at the rotor.
As to means for this weight adjustment, in Patent Document 1, a weight called dummy rack is used to reduce a weight difference between the buckets. On the other hand, Patent Document 2 discloses a technique in which weights of all racks are previously measured, and they are stocked once, and a pair of racks having a weight difference therebetween within a predetermined amount are selected from a group of the stocked racks and are inserted into the pair of buckets.
Patent Document 2 discloses a technique in which the difference in the weight between the adaptors positioned symmetrically to each other is minimized by providing a specimen-container weight-measurement mechanism in an automatic centrifuge, and repeating to compare total weights of the adaptors (adaptors A and B) with each other placed on a pair of buckets positioned symmetrically to each other across a centrifugal rotation center of a rotor so as to place a next specimen container on the adaptor B if the adaptor A is heavier, conversely, so as to place the next specimen container on the adaptor A if the adaptor B is heavier, and to compare the weights of the adaptors A and B again, until there is no vacant position on either one of the adaptors.